Study Type - Therapy (retrospective cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Erectile dysfunction following radical prostatectomy (RP) is among the most common and dreaded adverse effects of the surgery. Multiple studies confirm the potential benefit of various drug classes to accelerate the return of erectile function (EF) after RP. There is pre-clinical evidence supporting the use of angiotensin-receptor blockers (ARBs) for this purpose, although this has not been studied in humans. The present study shows that there may be a benefit in the recovery of EF post-RRP in patients taking a daily dose of irbesartan, an ARB, following RRP. In addition, the use of irbesartan may curb the loss of stretched penile length which occurs postoperatively. Further study in the form of prospective, randomized, placebo-controlled clinical trials are necessary to confirm these findings. OBJECTIVE: • To evaluate retrospectively the potential benefit of administering irbesartan, an angiotensin-receptor blocker, to improve erectile function (EF) recovery after nerve-sparing radical retropubic prostatectomy (RRP). PATIENTS AND METHODS: • Before surgery potent patients who underwent nerve-sparing RRP between April and December 2009 elected to start daily oral irbesartan 300 mg on postoperative day 1 (n= 17). A contemporaneously clinically matched cohort consisting of patients who declined irbesartan use served as the control group (n= 12). • Postoperative 'on demand' use of erectile aids (phosphodiesterase type 5 [PDE5] inhibitors and intracavernous injections) was adopted. • Potency was monitored by the administration of International Index of Erectile Function-5 (IIEF-5) questionnaires before surgery and at early (3 months) and long-term (12 and 24 months) postoperative intervals. • Stretched penile length (SPL) was measured both immediately and 3 months after surgery. RESULTS: • EF status was no different between groups at baseline (P > 0.05). • While the IIEF-5 scores at 24 months after surgery were statistically similar between the two groups (control = 15.2 ± 2.0, irbesartan = 14.1 ± 3.1, P= 0.77), at 12 months the IIEF-5 scores of the irbesartan group were significantly higher than those of the control group (14 ± 2.6 vs. 7.2 ± 1.6, P < 0.05). • The proportional loss of SPL after RRP was less in the irbesartan than in the control group at 3 months (-0.9 ± 1.5% vs -5.6 ± 1.5, P < 0.05). CONCLUSION: • Regular irbesartan use after nerve-sparing RRP in patients with normal preoperative erectile function could improve EF recovery after surgery and mitigate early loss of SPL.